1. Field of the Invention
The present invention relates to a mold for manufacturing a skin covered foamed plastic article such as that to be utilized as an automobile seat.
2. Description of the Background Art
Skin covered foamed plastic articles are generally used for automobile seat cushions, seat backs, and head rests. Such a skin covered foamed plastic article is usually manufactured by using a mold having an upper mold and a lower mold, and in addition a middle mold to be placed between the upper mold and the lower mold may be used, if necessary.
In such a mold for manufacturing skin covered foamed plastic articles, liquid foam resin is poured over a skin cover laid over the lower mold, which will subsequently stiffen to become a pad member combined with the skin cover in a cavity formed inside the assembled lower mold and upper mold. There is also a type of a skin covered foamed plastic article which incorporates frames such as a seat frame and a head rest frame by placing the frames on the skin cover before the liquid foam resin is poured.
The middle mold is often employed for making a hollow region in the pad member by dispelling the liquid foam resin, in order to reduce consumption of the liquid foam resin and the weight of the skin covered foamed plastic article.
Also, when the skin covered foamed plastic article is to be used as a seat back, it is necessary to make a head rest stay on the skin covered foamed plastic article. For this purpose, as shown in FIG. 1, in a conventional mold 1 comprising a lower mold 2, an upper mold 3, and a middle mold 4, a protrusion 5 for making the head rest stay is provided on the lower mold 2 or the middle mold 4.
Now, in such a conventional mold 1, the middle mold 4 is attached to the lower mold 2 and after the manufacturing is completed the middle mold 4 has to be removed from the lower mold 2 in order to take the manufactured skin covered foamed plastic article out. Thus, the attaching and removing of the middle mold 4 have to be performed for each skin covered foamed plastic article to be manufactured, which is quite cumbersome.
On the other hand, the middle mold 4 could not have been combined with the upper mold 3 in order to eliminate this attaching and removing of the middle mold 4, because of the danger of damaging the manufactured skin covered foamed plastic article by the protrusion 5 in disassembling the upper mold 3 from the lower mold 2.